Clear polyethylene, 3 In. W. x 6 Ft. H. x 1.25 mil. thick. 4 sheets per window kit. Fits 4 windows up to 34 In. W. x 70 In. H. Economical way to insulate wood framed windows. Provides an insulating barrier for comfort and fuel savings. Kit includes nails and fibre framing strips for easy installation. For outdoor use.